Monday 12 March 2007 11.14 EDT
First published on Monday 12 March 2007 11.14 EDT

The following correction was printed in the Guardian's Corrections and clarifications column, Wednesday March 14 2007

The Campaign to Protect Rural England wrongly appeared in the article below as the Council for the Protection of Rural England, a name it abandoned four years ago. This has been corrected.

A rundown Hertfordshire estate that BP bought in the 1970s as a safe investment for its pension fund may prove to be the best deal the company ever made.

The 1,500-hectare [3,700 acres] of wood and field north of Harlow cost the oil giant around £1m as farmland, but with planning permission expected to be given in the next year for up to 25,000 homes, along with business parks, offices and shops employing nearly 30,000 people, the land is now thought to be worth £9bn-£11bn - nearly as much as the fourth largest company in the world made out of extracting oil in 2005.

The trouble, say opponents of its plan to build a town for 60,000 people, is that at least half the BP land is designated metropolitan greenbelt, a green lung for London and the people of Harlow.

Pressure has been growing from developers and some politicians to relax greenbelt restrictions to ease a housing crisis in the south-east of England, driven by people moving for work as well as a steady flow of people from overseas into London. Government estimates say about 4m new dwellings will be needed by 2016.

But the need for more housing in the south-east is little comfort to those likely to be affected by the planned expansions.

"Not only does BP hit us with global warming, it now makes vast profits out of land that was protected for the public benefit," said John Clarke, who has been a resident in the village of Gilston for nearly 70 years and who lives in a BP-owned house. Gilston, with its beautiful Tudor church and orchards surrounded by green fields, will be near the centre of what BP's pension fund calls "Harlow North". It says this will be a "sustainable urban extension that builds on the pioneering spirit of Harlow New Town" created during the post-war period of London overspill construction.

"There is no comparison with the building of Harlow in the 1950s," said Mr Clarke. "Harlow was publicly funded. It was built to provide homes for the poor sods living in cowsheds after a vile world war. People wanted houses. The only opposition was from a few landowners.

"Now we have a giant corporation hand in hand with the government thundering across the countryside against everyone's wishes. "

But Hertfordshire stands to lose far more than the Harlow greenbelt. "We have four reviews of our greenbelt. The government plan gives us a minimum of 86,000 new homes, and we reckon about 30,000 will have to go on greenbelt land," said Jon Tiley, head of forward planning at Hertfordshire county council.

The precise locations are not specified yet, but most new houses are expected to go on greenbelt land near Hemel Hempstead, Hatfield, and on the edge of the M1. "Perhaps it is a coincidence, but three very significant landowners will benefit - BP, the Crown Estates and Arlington Securities, the former property branch of BAE," said Derrick Ashley, Hertfordshire cabinet member for planning.

"What makes it worse is that we have been told to consider development needs until 2031. This means we may need to put a further 30,000 houses in the greenbelt," said Mr Tiley.

"It's mindboggling. They have told us that compensatory greenbelt will be provided. But it will not be located anywhere near populations, so it is meaningless. People recognise that housing is needed ,but this is just industrialising the county," he said.

Greenbelt boundaries are also being reviewed in the other growth areas around London. The Upper Lee valley near Thurrock stands to lose thousands of acres, and south Bedfordshire and Luton are expected to take more than 40,000 houses, around 75% of which will have to be built on greenbelt land.

"Everyone accepts we need to build more houses, but the West Midlands has been told it must take up to 575,000. All the greenbelt land is threatened in the West Midlands," said Gerald Kells, local Campaign to Protect Rural England officer. "We estimate that 23 square miles of greenfield and greenbelt will be lost," he said.

Draft plans for the south-west of England propose six major changes to the boundaries of the Avon greenbelt which will almost certainly have to accommodate the expansion of Bristol airport, and the Royal Portbury dock, as well as four urban extensions. Present plans suggest 24,000 houses on greenbelt land.

Airports are expected to take large areas of greenbelt. Birmingham is seeking 290 hectares for its second runway; Bristol 200 hectares, and Manchester 270 hectares for a freight terminal. Gatwick wants 240 hectares for its second runway.